1. Technical Field
This invention relates to a rotating kiln having a tire injection system for injecting whole tires into the kiln such that the tires can be used as a source of supplemental heat for the kiln.
2. Discussion
Rotary kilns have heretofore been used to burn various forms of liquid and solid combustible waste as a source of relatively inexpensive supplemental heat. The extremely high temperatures within such kilns, which typically reach up to and above 3400.degree. F., combined with the long residence times of such waste within such kilns, have proven to be effective in completely combusting various forms of waste while producing little or no undesirable gaseous or solid emissions. Since such wastes form a supplemental source of inexpensive heat for a cement kiln, this also reduces the operating cost of the kiln.
One form of waste which has been heretofore used is worn out automobile and truck tires. Rubber tires burn extremely hot, and thus make a very good source of supplemental heat for a rotary kiln. The extremely high temperatures within a cement kiln serve to burn rubber tires without any significant liquid, solid or gaseous waste byproducts which might be detrimental to the environment. Since tires currently present a disposal problem, burning tires in rotary kilns serves to help alleviate the growing problem of insufficient means for disposing of used rubber tires without impairing the environment.
Prior art rotary kilns involving the injection of tires have typically suffered from several drawbacks. Initially, some systems require that the tires be cut and packaged into "fuel packages" having relatively specific outer dimensions. Such preparation of used tires obviously adds to the overall cost of operating the kiln and may also require the use of special equipment and additional manpower to cut the tires and package the resulting pieces into suitably sized packages.
Other systems allow entire tires, as well as other supplemental forms of fuel, to be inserted into the kiln but rely on gravity feed to accomplish this. Such systems frequently have some form of opening in the kiln wall with a loading area adapted to support a tire or other supplemental fuel source as the kiln rotates. When the loading area becomes disposed substantially vertically, gravity causes the tire or other fuel item to slide into the interior area of the kiln. The drawback with these types of systems is that the tire or other fuel item must be dropped into the highly fluidized material from a relatively high elevation, thus causing a splash in the material and creating excessive turbulence within the kiln. Therefore, using a gravity feed system, it has heretofore been necessary to insert each tire or fuel item (or "packet") while the tires or fuel items are positioned at or near the highest point of rotational travel of the kiln in order to make use of gravity in inserting the tires into the kiln.
It is therefore a principal object of the present invention to provide a rotary kiln having a means by which an item representing a supplemental form of fuel may be positively injected into the kiln during a portion of the rotational travel of the kiln, and which does not rely on gravity to accomplish the injection of the supplemental fuel item.
More particularly, it is an important object of the present invention to provide a cement kiln having a whole tire injection system which injects whole tires into the interior area of the kiln such that the tires come to rest in the bottommost portion of the kiln without causing splashing or other turbulence of the fluidized material within the kiln.
It is another object of the present invention to provide a cement kiln having a rotating tire injection system which operates to positively inject whole tires into an interior area of the kiln without relying solely on gravity feed, to therefore enable a plurality of whole tires or other fuel items to be injected into the kiln at virtually any point about the periphery of the kiln during a given revolution.
It is still another object of the present invention to provide a cement kiln having a tire injection system which does not require the used tires to be cut up or otherwise packaged in a specific manner, but instead allows entire tires to be injected into the interior area of the kiln as a supplemental heat source.
It is still another object of the present invention to provide a cement kiln having a whole tire injection system which includes structure within the cement kiln for keeping the highly fluidized material away from an entrance chute of the kiln during a predetermined degree of rotational travel of the kiln, thereby allowing whole tires to be positively injected into the kiln and the fluidized material to thereafter flow onto the injected tires, thus minimizing the turbulence created in the fluidized material by the tire injection process.
It is yet another object of the present invention to provide a rotary kiln having an injection system for injecting a wide variety of items representing supplemental sources of heat into the kiln, including but not limited to whole tires, shredded portion of tires, products, bundled paper and cardboard products, containerized waste products, pieces of coal, etc., or virtually any other form of supplemental fuel which is capable of being presented in packets, bundles, or pieces suitable to be forcibly projected into the kiln.
It is yet another object of the present invention to provide a cement kiln having a whole tire injection system which may be relatively easily fitted to existing kilns to allow whole tires to be positively injected therein.